In some cases you are presented the wrong page when trying to approve a task that was created by a Nintex workflow. The one you see is the original SharePoint page. While instead you should see the one with the option “Approve” and “Reject”

The problem here seems to be a mismatch in the connection between the taskform and a contenttype.

There is solution to this problem. You need to set the right taskform to be shown with the NintexWorkflowTask content type.
Use the nwadmin command line tool with the SetTaskForm operation

In some situations you will notice that the navigation option is missing from the site settings screen.

Modifying the global or the current navigation is not possible.
Or is it?

Yes, in fact there are two solutions.

The reason that the navigation option is missing is due to the fact that your site does not have the publishing functionality enabled.

Option 1

So enabling this feature will give you back the navigation option.

Go to Site Actions->Site Settings then under “site collection adminstration” section click on “site collection features”. Now Activate the “Office Sharepoint Server Publishing Infrastructure” feature. You need to be a site collection administrator to be able to activate this feature. Now for each site you can activate feature “Office SharePoint Server Publishing”. You are done. Now you should be able to see the navigation option.

Option 2

If you don’t want to enable the publishing feature you can use the quick link /_layouts/AreaNavigationSettings.aspx
Append this directly after the url for your site and you’ll be directed to the navigation modification screen.